Infectious diseases are responsible for the deaths of million of people every year. Although the use of vaccines and drug therapies has decreased mortality due to infectious diseases in developed countries, infectious diseases continue to be the leading cause of death in third world countries. In addition, many infectious diseases emerge or re-emerge in developed countries every year.
Recently, the public has become concerned about infectious agents for a number of additional reasons. The risk of bioterrorism, in which the public is exposed to biological agents, such as pathogenic organisms or agricultural pests for terrorist purposes increases in times of violence and war around the world. In addition, with the ever increasing number of people traveling to diverse regions of the world, infectious diseases once confined to distinct geographic areas can be spread to distant locations. In short, infectious diseases are a constant potential source for deterioration of the health of the population at large.
A number of treatments currently exist for some, but not all infectious agents. For some infectious diseases, for example, viruses including chickenpox, approaches to control focus on prevention of viral diseases, for example, by vaccination. Unfortunately, people or populations may not have been vaccinated and vaccines may not have been developed or may not be readily available (e.g., have not been stockpiled) for many viruses and infectious agents. Therefore there is a need for agents that can be used to treat infections. In addition, it is advantageous to develop therapeutics against new targets, in order to treat the deleterious effects of forms of infectious agents that have become resistant to presently available therapeutics, as well as those infectious agents that have been mutated or biologically altered.